From what others have experienced, how may days would be best to see each of these cities on one trip. Are taking the route Seville train to Granada then night train to Barcelona. We have 7 days including our arrival day but not our departure day. What would you do?

I think you're trying to do too much in such a short time. I would focus either on the north - adding to Barcelona - or the South - doing Seville, Granda and Cordoba (the latter three even being a lot for so few days). Otherwise you'll just spend too much time in transit versus enjoying the uniqueness of Spain.

with only 7 days, i would cut one place out. too much time wasted travelling around. Do one night in Granada and 6 in Barcelona. From Barcelona you can do several day trips, including to Figueres to see the Dali Museum and some of the beach towns. Seville is just too far.

Oh well we have tickets already into Seville and out of Barcelona, so how mant days are good for each, and Granada?

Well, if that is the case, I would do 2 days in Seville, catch an early AM train to Granada on the 3rd day, visit the Alhambra in the afternoon (buy tickets in advance) and then train it to Barcelona in the evening. I wouldn't bother staying over in Granada. Then you have 4 days in Barcelona. Not perfect, but doable.

thats what i was thinkin!